A number of tactile sensors are known to be useful in cybernetic applications, but each of the known devices suffers from disadvantages which have been overcome by the present invention. Contact sensors, or switches, have been used to sense an object, but these devices generally require a large space or surface area for pressure sensitive elements. See, DBR Pat. No. 2,556,780. Other contact sensors rely on some means of converting pressure to an electrical capacitance or inductive signal. See, USSR Pat. Nos. 769,331 and 901,831. A method of using an array or matrix of resistance-sensitive charge-generating elements is also known. See, Overton, U.S. Pat. No. 4,481,815. A photoelectric method is described in DBR Pat. No. 2,438,221.
The contact methods which rely on integral pressure sensitive elements require that the gripped object be perfectly clean, in order to prevent choking of the integral element channels. Contact sensors which employ an inductive resistance method require the generation of a minimum contact force, sufficient to shift a core, bend or stretch a tensometer, and secure a reliable contact. Capacitive contact sensors require the screening of electrodes in a multichannel arrangement. Photoelectric methods require light-reflective materials, and elastomeric materials require the use of a special amplifier.